This circuit has been used and continues
to be used for controlling the speed of universal motors in millions of
appliances, hand tools, and sewing machines throughout the world.

[3] Patent 3,275,909
Granted 9/27/66.

“Semiconductor Switch”.

This is the basic patent for the TRIAC AC
switch used worldwide in almost every lamp dimmer, static AC switch, and
electric heating control.

[4] Patent 3,404,327
Granted 10/01/68.

“Conversion Systems
Comprising SCRs with Gate Control Arrangements”.

This circuit patent is basic to at least
a half of all SCRs used in the world.It covers the use of SCRs in phase control circuits, the basis of
industrial motor drives of all horsepower ratings, battery chargers, and
lighting systems.

[5] Patent 3,535,615
Granted10/20/70.

“Power Control Circuits
including a Bidirectional Current Conducting Semiconductor”.

The patent covers basic circuits using
the TRIAC switch.All lamp dimmers
and static AC relays are covered by this patent.